The study will investigate how visual information is represented in the prefrontal cortex, the brain area involved with higher cognitive functions, before and after learning to perform a cognitive task. Monkeys will be trained in cognitive tasks that require them to observe and remember visual stimuli. Neurophysiological recordings with an array of microelectrodes at various training stages will allow us to determine the patterns of neuronal activation and the functional interactions between neurons. The experiments will uncover the nature of changes that take place in the prefrontal cortex by learning to perform a cognitive task. PUBLIC HEALTH RELEVANCE: The experiments will test what changes occur in the prefrontal cortex after subjects are trained to perform a cognitive task that requires visual, short-term memory. Cognitive training has shown promise in restoring function after traumatic brain injury, in ameliorating the effects of normal aging, and improving cognitive symptoms of disorders such as Alzheimer's disease. Our results will uncover the changes in brain circuits following cognitive training and offer insights on the design of better treatment strategies for dealing with cognitive decline associated with these conditions.